I think it might help to attach Trick Attack, and possibly Suiton, to the DoT required health. Its kind of a waste to Trick Attack something that has 2000 health remaining. Also, the routine will cast Suiton even if you already have the buff, so if you take a couple of seconds to get into position while Trick Attack and Kassatsu are up. I'm not sure if it would be better to immediately go into a Kassatsu Raiton after Suiton, or hold Kassatsu in case you need a second Suiton.